Over 150 injured in 7.3-magnitude quake in northeastern Japan

According to Tokyo Electric Power Company Holdings Inc, water in a used nuclear fuel pool spilled over but has not leaked in the Fukushima Daiichi Power plant, which has suffered nuclear meltdowns in a massive earthquake and tsunami catastrophe that hit the region 10 years ago.

Other nuclear utilities have reported no irregularities so far.

Japanese Prime Minister Yoshihide Suga said at a meeting of Cabinet members that the government has received reports of many injuries but no deaths.

He urged people to stay alert, noting quakes with a seismic intensity scale of Upper 6 could happen over the next seven days or so.

"We want people to take action swiftly without letting their guard down by paying close attention to information provided by local authorities," said Suga.

Up to 950,000 households were left without electricity at one point, but the blackouts had been solved by Sunday afternoon.